LAX98TA278

NTSB accident investigation · Aerospatiale SA316B · Porterville, CA · August 27, 1998

Accident · No injuriesFinal report
Date
August 27, 1998, 15:45 local (22:45 UTC)
Place
Porterville, CA
Injuries
1 uninjured
Damage
Substantial damage
Phase of flight
Maneuvering
Aircraft
N605RAAerospatiale SA316B
Weather
Visual (VMC) · Day
Status
Completed · report March 30, 2000
Report
Approved by Office Director
FAA report
19980827022279A
Case key
43825

From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.

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Probable cause

The pilot's failure to maintain adequate in-flight clearance between the bucket and trees resulting in the entanglement/separation of the long line and subsequent impact with and separation of the tail rotor assembly. A factor was the trees.

Sequence of events

NTSB’s coding before 2008: each occurrence and phase of flight, and the causes and factors under it. The codes are defined in NTSB’s coding manual.

Rotor failure/malfunctionManeuvering
External load cable/hook - entangledCause
Clearance - not maintainedPilot in commandCause
External load cable/hook - separation
Rotor system,tail rotor - separation
Object - tree(s)Factor
Terrain condition - mountainous/hilly
Loss of control - in flightDescent - uncontrolled
In flight collision with terrain/waterDescent - uncontrolled

Analysis

The helicopter had a bambi bucket on a 100-foot-long line. The bucket became entangled in some trees and the line snapped and wrapped itself around the tail rotor. The tail rotor blades and gearbox separated from the aircraft and the helicopter spun to the ground and rolled down a steep slope. The pilot did not report any mechanical malfunction with the aircraft prior to the accident. Wire marks were found on the tail rotor blades and around the output shaft.

Factual narrative

On August 27, 1998, at 1545 hours Pacific daylight time, an Aerospatiale SA316B, N605RA, operated by the U.S. Department of the Interior, sustained substantial damage after entangling a bambi bucket in a tree near Porterville, California. The airline transport pilot, the sole occupant, was not injured. The public-use aircraft operating under 14 CFR Part 91 was performing a fire mission at the time of the accident. No flight plan was filed and visual meteorological conditions prevailed.

Witnesses saw the helicopter fly down the side of a ridge with the bambi bucket on a 100-foot-long line. The bucket became entangled in some trees and the line snapped and wrapped itself around the tail rotor. The tail rotor blades and gearbox separated from the aircraft and the helicopter spun to the ground and rolled down a steep slope. Witnesses reported that the terrain was mountainous, with 40 to 50 degree slopes. The pilot did not report any mechanical malfunction with the aircraft prior to the accident.

A Federal Aviation Administration inspector from the Fresno, California, Flight Standards District Office traveled to the site and reported that there were wire marks on the tail rotor blades and around the output shaft of the gearbox.

Aircraft

Registration
N605RA
Reported as
Aerospatiale SA316B
Category
Helicopter
Serial number
1165
Airframe hours
3,305
Engine
Turbomeca ARTOUSTEIIIB, 858 horsepower, turbo shaft
Damage
Substantial damage
Flight
Public aircraft · Part 91
Operator
U.S. Dept. Of The Interior
Registered owner
Roberts Aircraft Company
Airworthiness certificate
Standard, Normal
Last inspection
Annual · May 14, 1998 · 230 hours before

Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.

Flight crew

As NTSB recorded them. NTSB leaves out names.

Role
Pilot
Age
54
Certificates
Airline transport, Flight engineer
Airplane ratings
Single-engine land, Multi-engine land
Instrument ratings
Airplane, Helicopter
Medical
Class 2, Valid Medical--w/ waivers/lim
Seat
Right
Flight hours
9,900 total · 3,300 in this make and model · 8,700 as pilot in command · 95 in the last 90 days · 51 in the last 30 days · 1 in the last 24 hours

Weather

Conditions
Visual (VMC) · Day
Wind
270° at 10 knots, gusting 15
Visibility
10 statute miles
Lowest ceiling
None
Temperature
95 °F, dew point 57 °F
Altimeter
29.00 inHg

FAA reports on this event · 1

The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.

Other investigations on N605RA · 1

Matched to the same aircraft by N-number and date.